When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
A few have requested a dyno comparison of a stock GT4 to my Stage II car. That comparison is attached below.
Stage II GT4 / Mods Include: BMC Filters, Aasco Lightweight Flywheel, 82mm Throttle Body, 991 GTS/X51 Power Kit (Intake Manifold, Ported Cylinder Heads & Intake Cams) with Cargraphic Stainless Steel Longtube Manifolds. Dyno run is with stock X51 991 GTS mapping - PRE TUNE & WITH STOCK PSE!
Within the next 2 weeks we are wrapping up a 2016 Boxster Spyder with the Stage III 3.99L Stroker Conversion. I will produce another comparison of this car vs. my car which will be relevant because both cars are running race headers, lightweight flywheel, X51 Upgrade, BMC Filters, etc with the Stage III car running the different stroker parts. This should be a good apples to apples comparison of Stage II vs. Stage III.
A few have requested a dyno comparison of a stock GT4 to my Stage II car. That comparison is attached below.
Stage II GT4 / Mods Include: BMC Filters, Aasco Lightweight Flywheel, 82mm Throttle Body, 991 GTS/X51 Power Kit (Intake Manifold, Ported Cylinder Heads & Intake Cams) with Cargraphic Stainless Steel Longtube Manifolds. Dyno run is with stock X51 991 GTS mapping - PRE TUNE & WITH STOCK PSE!.
Nice increase at 5k, eliminated the power dip, and above 6.5k, it looks like it's breathing with all 6 lungs! Good strong HP pull all the way to 7.5k+.
I was wondering why I couldn't pull a 3.4 Cayman S by even an inch after he gave me a pass coming up out of the toe of the Boot at the Glen. Having seen the graph, now I know. Forget the redline - it looks like short shifting is the ticket.
Within the next 2 weeks we are wrapping up a 2016 Boxster Spyder with the Stage III 3.99L Stroker Conversion. I will produce another comparison of this car vs. my car which will be relevant because both cars are running race headers, lightweight flywheel, X51 Upgrade, BMC Filters, etc with the Stage III car running the different stroker parts. This should be a good apples to apples comparison of Stage II vs. Stage III.
A few have requested a dyno comparison of a stock GT4 to my Stage II car. That comparison is attached below.
Stage II GT4 / Mods Include: BMC Filters, Aasco Lightweight Flywheel, 82mm Throttle Body, 991 GTS/X51 Power Kit (Intake Manifold, Ported Cylinder Heads & Intake Cams) with Cargraphic Stainless Steel Longtube Manifolds. Dyno run is with stock X51 991 GTS mapping - PRE TUNE & WITH STOCK PSE!
Within the next 2 weeks we are wrapping up a 2016 Boxster Spyder with the Stage III 3.99L Stroker Conversion. I will produce another comparison of this car vs. my car which will be relevant because both cars are running race headers, lightweight flywheel, X51 Upgrade, BMC Filters, etc with the Stage III car running the different stroker parts. This should be a good apples to apples comparison of Stage II vs. Stage III.
Hmmmm. Something looks odd to me. The stock engine dynos do dip at the end usually, but this dip looks rather large compared to other ones I have seen before .....
Hmmmm. Something looks odd to me. The stock engine dynos do dip at the end usually, but this dip looks rather large compared to other ones I have seen before .....
Most don't go past 7500 rpm, if that scale is correct.
Hmmmm. Something looks odd to me. The stock engine dynos do dip at the end usually, but this dip looks rather large compared to other ones I have seen before .....
I humbly disagree. I feel like the stock curve looks better than most that I've seen, but only because of the scaling (stretched horizontally). The dips may look worst since they're being compared to an yummmmmy almost perfectly linear power curve. Reminds me of an S54 from my bimmer days. x51 looks superb!
I humbly disagree. I feel like the stock curve looks better than most that I've seen, but only because of the scaling (stretched horizontally). The dips may look worst since they're being compared to an yummmmmy almost perfectly linear power curve. Reminds me of an S54 from my bimmer days. x51 looks superb!
Agree. Stock GT4 chart from page 6 of this thread -
And again on page 50 -
If you ignore the x axis vs y axis scale, they all look a lot like the stock chart on this page.
Wow, interesting dyno runs!! When looking at the graphs, I had not noticed how flat the power band gets around 6600. The scale and comparison on the BGB graph emphasizes that characteristic. The motor pulls harder from 5400 to 6400 then flattens out. You can really tell the car is pulling with more power once you hit about 5400rpm until about 6400. This is noticeable when driving. The car continues to accelerate fairly good above 6400 but it doesn't really feel as if it is pulling harder or "taking off". The Cayman ("Little Brother") handicap! That said, I still love the car and it is nice to know there is plenty of upward potential for the platform.
Just a few thoughts in response to that awesome "stage II" dyno on the previous page.
1. I've noticed from reading others' experiences that running aftermarket ecu tuning has had a few teething issues (CELs, hung throttle) and that, conversely, using the GTS map on the GT4 makes it run well, but some of the other features don't work (PASM/TC, I think). If I were to upgrade my car, I'd prefer a solution that uses the factory GTS map if someone could get everything else to work, over using aftermarket tuning. I don't mind if I get 10 less hp with the GTS map compared to something like COBB, I'd prefer the factory GTS tuning.
2. It still seems hard to get apples to apples hp gains from headers, however, perhaps roughly it's a 5-10 hp gain from sport catted headers, and 20 from "race" headers. I think I'd prefer to leave the headers stock because I'd need cats 10 hp might not be worth it.
So, down the line, if I were to upgrade, I'd like "82mm Throttle Body, 991 GTS/X51 Power Kit (Intake Manifold, Ported Cylinder Heads & Intake Cams) with a GTS map" which appears like it would give 50-54 hp at the wheels because the previous page of this thread shows a 74 hp gain at the wheels with the above AND long tube headers. Without long tube headers, 440-445 hp at the crank would be plenty
08-15-2016, 05:57 PM
